awhile ago my car was misfiring while accelerating but not leaving any codes. i knew it wasnt the sparks plugs, coil packs, or the fuel pump because i ahad just replaced these parts. i figured out it was the head gaskets because it was leaking antifreeze on two of my spark plugs. i used a product called head gasket repair and it stopped the problem completely. this time its doing the same thing but its not leaking antifreeze anywhere. i tried the head gasket repair again but this time it didnt work or even help the problem.